S2 Crank but no start. Low d09

[TownsendsFJR1300]

That starter is spinning just fine, I don't believe there's any excess load to the starter.
Lights would dim, but not go on and off entirely at the dash(as if turned off)..

The entire dash going dead, on and off occasionally is one of your issues.

As stated earlier, try a spritz of starting fluid while cranking down the TBs, see if it lights off immediately.

We need to start narrowing down the issue, fuel, spark, compression, etc.


.

 

[jomor147]

Yes I agree, when I say massive load, I don't mean continuously, but after let's say 5 seconds of normal cranking (and normal mechanic load) something gets blocked, stopping immediately the starter, I feel it like two metal parts hit each other and at the same time the voltage collapses as a consequence. But I m listening, keeping in mind what you are saying.

 

[Gary in NJ]

Get an electric motor hot enough that there is thermal expansion, then the air gap disappears leading to the rotor and stator rubbing together. That's a significant physical block.

Honestly, you are abusing that starter motor. Run it for 5-10 seconds, and then allow it to cool for 2-4x the run time (depending on the duty cycle; less for one cycle, more for multiple cycles).

 

[Motogiro]

This is interesting. Yes you are going beyond duty cycle on the starter. That looks like a wide open circuit, except for the sound it make at the same time.
First why isn't it firing .....
My other thought is that if it's a voltage drop do to high current draw, we might hear the starter relay chattering as it opens during voltage drop then re-engages as the voltage returns. it's also emulating a wide open.

 

[TownsendsFJR1300]

It obviously should be lighting off immediately.

No more than 1-2 seconds.

Back to basic's, check for fuel (getting there immediately).
Again, a spritz of carb cleaner (or equivalent), when cranking, plz post if it lights off or not.

If it doesn't lick off, likely lack of spark (apparently / possibly) an intermediate issue.

If it does lick off, concentrate on the fuel system... A fuel pressure gauge to see what the rail
pressure is, is probably quite necessary at this point..

.

 

[jomor147]

This is interesting. Yes you are going beyond duty cycle on the starter. That looks like a wide open circuit, except for the sound it make at the same time.
First why isn't it firing .....
My other thought is that if it's a voltage drop do to high current draw, we might hear the starter relay chattering as it opens during voltage drop then re-engages as the voltage returns. it's also emulating a wide open.

The sound is together with a knocking, i can feel a metal part hitting another.

Today i had the following: I primed 5 -6 times before cranking. I pressed the starter button for 3 - 4 seconds and it did not start. Primed ( = ignition switch off-on) two or three times. Cranked for a few seconds then the mechanical block happened, i kept the starter button pressed and it started immediately. What was different this time was that i did not release the button, the block happened, the voltage collapsed but not completely, immediately when the knocking was felt the engine started. This is more confusing to me, since i was turning towards the fuel pressure direction, now i am thinking again if its something in the starter clutch or starter itself. And the problem is that its intermittent, when the bike was at the mechanic she behaved like a lady. What i have to do from now on is to have my hand at the exhaust during cranking, won't i feel if the starter engages an the engine turns or not?

I understand what you all say about stressing the starter, i get stressed and do not think clearly while the issue is happening, i will follow your advice.

 

[jomor147]

It obviously should be lighting off immediately.

No more than 1-2 seconds.

Back to basic's, check for fuel (getting there immediately).
Again, a spritz of carb cleaner (or equivalent), when cranking, plz post if it lights off or not.

If it doesn't lick off, likely lack of spark (apparently / possibly) an intermediate issue.

If it does lick off, concentrate on the fuel system... A fuel pressure gauge to see what the rail
pressure is, is probably quite necessary at this point..

.

Its an intermittent problem and if it does not happen while the bike is at the mechanic, its not easy for me to check for spark in the street, but i will have to do it myself at the end.

So if i lift the tank and spray for 2 seconds towards the airbox opening from a distance lets say 20cm will this work ? never tried this procedure.

 

[TownsendsFJR1300]

Pull the air filter, Spray a second or two down each throttle bore.

The engine spinning over quickly rules out the starter or starter gear, being
an issue...

I'd bing it back to the mechanic as the issue is obviously still there. Let him ride it/take it home if need be, till
it acts up...


.

 

[jomor147]

The bike is at the mechanic for more than a week now and still can't get this sorted. He must have checked it once, saying that the fuel pressure gauge went to 3.2 bar when primed. No indication of injector leaking too, as he said. But the problem is intermittent so no safe results. It's disappointing to see a bike never having starting problems coming out from a service ( fuel pump replacement, injector cleaning, throttle body adjustment) with a starting problem and the mechanic not being able or willing to cure the problem which seems it probably appeared on his hands. I will get the bike and try to do his work (and also go to another garage obviously).

How can I have a visual indication of having a spark ? Do ebay inductive tachometers work on modern engines with insulated spark plug cables?

If I connect a led (with a 1k5 resistor) in parallel with the igntion coil input, will the extra 7-8mA stress the ecu negative trigger outputs? Will I get an indication this way ? ( I won't know the coils are healthy but at least i will see the ecu sends a signal)

 

[TownsendsFJR1300]

How can I have a visual indication of having a spark ? Do ebay inductive tachometers work on modern engines with insulated spark plug cables?

Keep it simple.

-Get a / some known good OEM spark plugs.

-Pull one at a time, the spark plug wire from the already / installed plugs.

-Attach to the new plug to the wire, ground it to the head/block, etc and crank the engine over.
You should EASILY SEE SPARK...

Were all replaced OEM parts, or after market?

.

 

[jomor147]

Aftermarket. The fuel pump is an Italian brand called RMS. My car mechanic (not the bike one) is quite disappointed with aftermarket parts quality the last 3-4 years, brands he trusted for decades have degraded too much their quality lately.

I just realized with the help of AI that I might have a vapor lock issue. If there is a fuel pressure loss after turning off a hot engine, the fuel in the fuel line gets boiled and a foam of bubbles blocks pure fuel injection, that's why it fails to start with one prime even though the pressure raises to 3.2bar as the mechanic verified. On the fist prime the pump just compresses the enclosed air. Priming many times pushes the air out and the engine starts. This also explains why the issue does not appear at the mechanic. He just tries it for 5 minutes in a controlled environment, never bad the bike running very hot like I do in the summer traffic. Next difficult task is to convince him for the above theory.

 

[Gary in NJ]

Vapor lock is not a known problem on the FZ6.

The fuel pressure going to 3.2 bar is a problem as it should be 2.5 bar. It’s an indication that the fuel pump assembly is not to OEM specification.

Check for spark as noted above. No need to remove the spark plugs…you just need access to the caps.

 

[jomor147]

Vapor lock is not a known problem on the FZ6.

The fuel pressure going to 3.2 bar is a problem as it should be 2.5 bar. It’s an indication that the fuel pump assembly is not to OEM specification.

Check for spark as noted above. No need to remove the spark plugs…you just need access to the caps.

Omg you re right, just verified what you said on the service manual. But shouldn't the pressure regulator adjust it to 2.5bar no matter what the pump gives ( as long it gives more than 2.5 ) ?

IF the pressure gauge measures accurately, doesn't this mean that I have a rich fuel mixture? Will rich mixture cause crank but no start or just increased consumption?

The mechanic replaced just the cartridge, not the full assembly. Which means if the pressure regulator was already bad I should have starting issues in the past too. The issue appeared just after replacing the cartridge.

 

[jomor147]

So to sum up: we want 2.5 bar fuel pressure just before the engine starts and during the engine operation, and maintain this pressure after turning off at least until the engine is cold. Am i correct?

 

[Gary in NJ]

2.5 bar all the time.

 

[jomor147]

Can't find the pressure regulator part number at yamaha online catalogue. And I only find aftermarket universal regulators at 3.5 bar. Is it available as a genuine seperate part or as an aftermarket at 2.5 bar, does anyone know?

AI claims that the issue might not be the regulator but the pump motor itself:
Why the Regulator is Failing to Stabilize the Pressure:
The webpage context shows that this aftermarket RMS pump operates at a base pressure of 3.0 to 4.7 bar (43-68 psi) with a massive flow rate of 140–160 Liters per Hour. [1]
The factory Yamaha FZ6 regulator reduces pressure by allowing "excess" fuel to pass through a tiny relief hole and dump back into the gas tank. Because this new RMS pump flows a much higher volume of fuel than the original factory motor, the fuel volume completely overloads the regulator's bypass capacity.

could this be the case?

 

[tuning-forks]

The mechanic replaced just the cartridge, not the full assembly. Which means if the pressure regulator was already bad I should have starting issues in the past too. The issue appeared just after replacing the cartridge.

By 'cartridge' I assume you mean the actual fuel pump motor within the assembly. In that case, the stock regulator is still in the assy.
Working on the assy. may have dislodged particles that may have got into the regulator and caused sticking. Or just the new pressures it is dealing with may have caused sticking. In any case, if it is allowing pressure to rise to 3.2 bar, it must be sticking or now defective. If it can stick too high, it can also stick too low, and that may be causing your intermittent issue.
The regulator is not available separately from Yamaha, they only sell the entire assembly. It is tough to find an aftermarket regulator at the correct pressure, no one has posted any that are 2.5Bar. You can probably find 3 bar and that would probably work ok.
There are other discussions on the forum where people have been able to clean out the regulator and get it to work right, but it may not last.
Have a look at this thread for cleaning info and more: https://www.600riders.com/threads/new-member-2008-questions-key-wheel-lockup.60742/page-3
Also look closely at these pictures regarding problems in reassembling the unit: https://www.600riders.com/threads/d...ing-engine-off-and-on-again.59931/post-649108

 

[jomor147]

Yes, cartridge = fuel pump motor, apologies for my bad english.

Thank you very much for posting this very useful info.

just spoke to the mechanic. He had the pressure gauge connected and most of the times he had 3.2 bar. Once the pressure was lost so he decided to replace the pressure regulator, fitting a used one from another pump and he has now the bike giving 3.2 again, as he insists that this is the correct value and 2.5 is the minimum required to work correctly. I mentioned the rich mixture consequence but he said that its a small variation between the accepted limits. Go figure. He also told me that even if i pay for a genuine pump assembly ( around 800 euros ) the pressure will be 3.2 as he had measured in the past. I am starting to believe - and hope - that his gauge is not accurate at all. He also mentioned that there is no o-ring issue and the only reason to loose pressure down to zero (as it happened to him once) is the pressure regulator and not the pump motor itself so he removed the gauge just after replacing the regulator and told me to get the bike tomorrow. I would have left it at least for a day to monitor the pressure and verify everything is coccreted before calling the customer. I ll get the bike tomorrow and see what happens.

 

[jomor147]

Found this on Ali but doesnt mention yamaha. Visually seems the same as far as I can tell but who can tell if it is ok to try. I m still confused if the 2.5 is the exact strict value or a minimum acceptable. As I read the manual I understand strictly 2.5 as you also mention, but there are many unofficial references online saying 2.5 is the minimum which creates a confusion

 

[Gary in NJ]

Your mechanic sucks.

The fuel pressure is 2.5 bar….period. Fuel injection systems are not designed to work within a range, but at a specific value. This way the system is able to provide an exact metered amount of fuel.